Water filter system

ABSTRACT

A slow/intermittent sand filter that purifies polluted water by flowing through sand in a manner that achieves greater purity and permits simpler and more effective maintenance than existing filters.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application Ser.No. 61/354,387 filed Jun. 14, 2010, and entitled WATER FILTER SYSTEM,incorporated by reference herein in its entirety.

FIELD

This disclosure relates to the field of water purification devices. Moreparticularly, this disclosure relates to a slow/intermittent sand filterthat purifies polluted water by flowing through sand in a manner thatachieves greater purity and permits simpler and more effectivemaintenance than existing filters.

BACKGROUND

A major issue that persists in underdeveloped areas is both waterquality and quantity. Slow and/or intermittent sand filters are a goodchoice for such areas in that they are generally of simple andinexpensive construction and do not require the use of electricity,chemicals or other materials that require replacement. However,conventional slow sand filters still desire improvement in that they donot adequately eliminate many bacteria and are not user friendly byilliterate and unsophisticated peoples due to their maintenancerequirements

The present disclosure advantageously provides improved slow and/orintermittent sand filter devices having improved construction and whichoffer simplified maintenance as compared to conventional slow sandfilters. The filters are of low cost and easily used so that the massesin undeveloped countries may have better access to cleaner water.

SUMMARY

The above and other needs are met by a water filtration system which, inone aspect, includes a treated water container and a water treatmentcontainer located substantially within the treated water container. Thewater treatment container is configured to receive untreated water andto treat the untreated water to yield treated water that is passed tothe treated water container for storage and/or dispensing.

The water filtration system includes a treated water container and awater treatment container located substantially within the treated watercontainer. The water treatment container is configured to receiveuntreated water and to treat the untreated water to yield treated waterthat is passed to the treated water container for storage and/ordispensing.

The treated water container includes a container having a bottom and asidewall extending upwardly from the bottom. The water treatmentcontainer includes an upper section configured to receive a volume ofwater to be treated; a first and a sand containing section within thecontainer and below the upper section having sand that includes abio-layer having a thickness at the uppermost portion of the sand. Asand separator is located within the sand containing section and in flowcommunication with the water treatment container. The sand separator isconfigured to separate sand in the water treatment container fromtreated water passing to the treated water container.

A flowpath extends from a location within the sand separator to alocation outside of the sand separator defining a treated water output,the treated water output being located at a height above an uppersurface of the sand in the sand containing section of the watertreatment container.

In another aspect, the disclosure relates to a water treatment containerconfigured to receive untreated water and to treat the untreated waterto yield treated water. The treated water container includes a containerhaving a bottom and a sidewall extending upwardly from the bottom. Thewater treatment container is configured to receive a volume of water tobe treated and includes a sand containing section having a bio-layerhaving a thickness within the water treatment container. The water to betreated passes through the bio-layer at a flow rate of about 0.10 metersper hour or less.

In yet another aspect, the disclosure relates to a method for purifyingwater, which includes the steps of, providing a water treatmentcontainer having a sand containing section within the water treatmentcontainer having sand that includes a bio-layer having a thickness atthe uppermost portion of the sand, and maintaining flow conditions sothat the water passes through the bio-layer at a flow rate of about 0.10meters per hour or less.

Water filtration systems according to the disclosure advantageouslysimplify filtration of water, achieving greater purity, and havesimplified maintenance requirements and reduced maintenance frequency ascompared to conventional filtration systems.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of the disclosure are apparent by reference to thedetailed description when considered in conjunction with the figures,which are not to scale so as to more clearly show the details, whereinlike reference numbers indicate like elements throughout the severalviews, and wherein:

FIG. 1 is an exploded perspective view of a water treatment systemaccording to the disclosure.

FIG. 2 is a cross-sectional perspective view of the water treatmentsystem of FIG. 1.

FIG. 3 is a perspective view of the water treatments system of FIG. 1,with a treated water container component thereof shown in phantom.

FIG. 4 is a perspective view of a water treatment container of the watertreatment system of FIG. 1.

FIG. 5 is a cross-sectional view of an interior water treatmentcomponent of the system of FIG. 1.

FIG. 6 is a cross-sectional view showing sand disposed in the watertreatment container and having a bio-layer.

DETAILED DESCRIPTION

With reference to the drawings, the disclosure relates to a slow sandfilter system 10 configured for removing dirt, sticks, microorganisms,and bacteria from polluted input water so that output water from thefilter system 10 is significantly cleaner and purer than the inputwater.

One of the main ways that slow sand filters perform is by passing waterthorough a bio-layer, a layer of sand that is approximately two inchesthick beneath the supply water interface. This layer develops overseveral weeks wherein bacteria lodge in the sand and feed on thepollutants and dissolved organic matter and help to improve the qualityof the treated water. It is important to let this layer develop and tolimit the speed of flow through the layer so that it has time toadvantageously treat the water. Over time this layer becomes cloggedwith solids so that water cannot flow through the layer fast enough tomeet the needs for treated water. At that point, the bio-layer may beacted on by (1) carefully stirring the top inch or so of the layer tomechanically dislodge the clogging solids and suspend the solids backinto the layer of water over the sand, and (2) removing the water withthe suspended solids. This “bio-layer cleaning” step is a delicateoperation as it can damage the bio-layer causing it to be less effectivethan needed, and requiring an additional bacteria development timeperiod before it works again as needed.

The filter system 10 of the disclosure is advantageously configured toreduce the frequency of performing, if not eliminate, the need for abio-layer cleaning step. As will be appreciated, reducing the need forsuch a bio-layer cleaning step advantageously renders the filter moreuser friendly, more constantly functional, and accessible for use by themasses.

With reference to the drawings, the filter system 10 includes anexterior treated water container 12 and an interior water treatmentcontainer 14 located substantially within the exterior container 12. Thecontainers 12 and 14 are sized to have substantially similar volumecapacities. The treated water container 12 serves as a reservoir forreceiving and holding water treated by the water treatment container 14of the filter system 10. The water treatment container 14 receivesuntreated water and treats the untreated water to yield treated waterthat is passed to the treated water container 12 for storage and/ordispensing.

The treated water container 12 is an open topped container having abottom 16 and a cylindrical sidewall 18 extending upwardly from thebottom 16. The container 12 is made of a fluid impermeable material suchas molded plastic.

The treated water container 12 is wrapped around the water treatmentcontainer 14 or otherwise nested with the water treatment container 14such that the treated water is part of the overall filter system 10. Thewrapped or nested construction is believed to significantly reduce thepossibility of recontamination of the treated water as compared toconventional filter systems which typically route the treated water to aseparate collection container externally remote from the portion of thefilter in which the water is treated. In this regard, it has beenobserved that recontamination has been found to be a significant problemin furnishing clean water to the user, and the described configurationis believed to substantially eliminate one of the most common sources ofrecontamination.

Treated water obtained by the treated water container 12 from the watertreatment container 14 is dispensed from the treated water container 12by gravity through a tap 22 located on a lower portion of the sidewall18 of the treated water container 12. The tap 22 includes a valve fed bya conduit structure configured as a tube within a tube at the outletsuch that if the outer tube is compromised, the inner tube remains outof reach and untouched. The treated water is dispensed via the tap 22into the end user's container, typically a drinking cup or a cookingvessel. A removable mouthpiece 23 may be attached to the tap 22 topermit a person to place their mouth adjacent the tap 22 withoutcontaminating the tap 22, with the mouthpiece 23 being personal to auser and removed after their use.

Matching the volume capacity of the treated water container 12 to thevolume capacity of the water treatment container 14 according to thedisclosure is advantageous to provide a stored volume of treated waterso that the low flow speed of water through the system 10 is notdetrimental to the typical needs of a home user using the system 10 toprovide drinking and cooking water.

For example, the containers 12 and 14 may be configured to each have acapacity of 5 gallons. A user needing 5 gallons of treated water for themorning would then put five gallons of water to be treated into thewater treatment container 14 at bedtime, and five gallons will beavailable by morning, since the system according to the disclosure whichtravels water through the bio-layer thickness at a desired average rateof about 0.03 meters per hour yields treated water at a rate of aboutone half (½) gallon per hour. That is, in one hour the water will flow,on average, through about 0.03 meters of the thickness of the bio-layer.To achieve this, as explained more fully below, the filter system isconfigured so that water passes through the bio-layer at a flow rate ofabout 0.10 meters per hour or less.

Conventional filters typically have no output container and are designedfor quick treatment, such that if a user wants a glass of water, theneeded volume is introduced and the treated water is dispensed within aminute or two, with such high production speed compromising both qualityof the treated water and immediately available volumes. Thus,conventional filters typically pass water through the bio-layer at ahigh rate about 10 times higher and produce about 16 gallons of treatedwater per hour. Contrary to conventional filter structures, the filtersystem according to the disclosure passes water very slowly through thebio-layer, as explained more fully below.

The relevant volume of the treated water container 12 corresponds to thevolume provided with the water treatment container 14 installed onto thetreated water container 12 below a treated water output port 24 of thetreatment container 14, generally corresponding to a water level L asshown in FIG. 2. Thus, if the treatment container 14 is configured toreceive in batch 5 gallons of water for treatment, the treated watercontainer 12 is sized so that the water level L corresponds to 5gallons.

The water treatment container 14 is configured to have an upper section30 configured to receive a volume of water to be treated. For example,if the system 10 is designed to treat 5 gallons of water as in theexample set forth above, the upper section 30 is sized to hold 5 gallonsof water. The upper section 30 includes a circumferential lip 32configured to engage a corresponding upper peripheral edge of thetreated water container 12. A removable upper debris screen or filter 34is set into a filter tray 35 located within the upper section 30 toremove larger sized debris that would tend to quickly clog the sandcontaining portion of the filter system 10. The filter tray is abowl-shaped plastic part having a slotted or aperture bottom. The upperdebris filter 34 is held in place by a retainer 34 a and the upperfilter 34 may be easily removed regularly for cleaning, as by rinsing orshaking, and then replaced.

A lower debris screen or filter 36 (held in place by a retainer 36 a) ispreferably located in the upper section 30 and spaced below the filtertray 35, but above an intermediate section 37 located between the uppersection 30 and a lower section 38. The intermediate section 37 and thelower section 38 are both filled with sand.

The retainers 34 a and 36 a are each provided as by sections offlexible, preferably plastic, tubing that are positioned within annulargrooves 34 b and 36 b, respectively, on the interior sidewall of thecontainer 14. The opposite ends of the plastic tubes butt against oneanother resulting in outward forces to retain the filters in place.Thus, each debris filter is placed adjacent one of the grooves and theplastic tubing is installed in the groove and the plastic tubingprovides an outward force to retain the debris filter in place.

The outlet port 24 is preferably located at a height that corresponds toa height of about 2 inches above the upper surface of the sand in theintermediate section 37 (dashed line S in FIG. 3). This positioning ofthe outlet port 24 relative to the bio-layer (designated B in FIG. 6)provided by the uppermost portion of the sand S is desirable both toassure that with intermittent flow the water is maintained at that levelso that even with evaporation that might take place in hot climates overdays or weeks, the bio-layer is protected from drying out.

This lower filter 36 can easily be changed or cleaned, again to protectthe bio-layer represented by the top layer of sand in the intermediatesection 37 from disturbance or the need for it to be delicately cleanedlater on. In this regard, the combination of the upper and lowerremovable filters advantageously enable improved ease of maintenance andwith more effective results of the filter system 10.

Another significant aspect of the disclosure relates to theconfiguration of the intermediate section 37 and the lower section 38.As seen in the drawings, the intermediate section 37 has a taperedsidewall so that the intermediate section 37 decreases or tapers incross-section as it approaches the lower section 38. The lower section38 decreases or tapers in cross-section as it approaches a bottom 40thereof.

For the purpose of example, for the system 10 configured to treat about5 gallons of water, the upper section 30 has a diameter of about 13inches and is round in cross-section. The intermediate section 37 has adiameter of about 11 inches which tapers to a diameter of about 7 inchesat the bottom of the intermediate section 37. The lower section 38 has adiameter of about 7 inches, which tapers to a diameter of about 4 inchesat the bottom of the lower section 38. A sand separator 42 is located onand extends upwardly from the bottom 40 of the lower section 38.

As will also be appreciated, the drawings of the described embodimentshow that the containers 12 and 14 extend to substantially the sameheight. This is advantageous to prevent overflowing of the treated watercontainer 12 without overflowing the water treatment container 14.

The sand separator 42 functions to separate the sand from water leavingthe water treatment container 14 and provides a vertical chamberconfigured as an inverted cone having an open bottom 44 located aroundan upward bulge 46 (FIG. 5) centrally defined on the bottom 40 of thelower section 38 of the container 14. In this regard, it has beendiscovered that the sand separator 42 may be provided as by a plasticdrinking cup, such as a disposable plastic drinking cup of a volume ofabout 16 ounces. This enables reductions in costs and ease of findingreplacement components.

The bottom 44 of the sand separator 42 (e.g., corresponding to the toprim of a plastic drinking cup if such is used) has a diameter of about75% of the bottom 40 of the lower section 38, or about 3 inches for thedescribed example system 10. A lower opening 48 is centrally located onan uppermost portion of the bulge 46. A generally J-shaped tube orconduit 50 is located within the separator 42. The tube 50 begins at alocation spaced below the top of the sand separator 42 and extendsdownward through the opening 48 of the bulge 46 and then turns to runupwardly along the outer surface of the water treatment container 14until terminating to provide the output port 24.

The filter system 10 is configured so as to not require a specific sandparticle size or composition. However, a significant aspect of thedisclosure is providing a structure that has a relatively slow flow rateF of water through the bio-layer B, which, as shown in FIG. 6 typicallyhas a thickness of about 2 inches. The volumetric flow rate of waterwill depend upon the volume of the sand S, and hence the size of thetreatment container. However, it has been discovered that a key aspect,regardless of the total volume of the water treatment container, is tohave a flow rate through the bio-layer B of about 0.10 meters per houror less. That is, in one hour the water will flow, at most, throughabout 0.10 meters of the thickness of the bio-layer B.

The maximum flow rate is usually achieved at the beginning of theprocess, when the water to be treated is provided to the treatmentcontainer. Over time, as the hydrostatic head decreases, the flow ratewill decrease. Thus, it has been observed that if the maximum flow ratethrough the bio-layer B is about 0.10 meters per hour, the average flowrate through the bio-layer B will be about 0.03 meters per hour.

This low flow rate may be achieved by having, in combination with thedescribed reduced cross-section of the lower portion of the container14, a sand composition that provides such a flow rate, with finer sandcompositions providing slower flow rates than coarse compositions.However, in the event the available sand composition does not achievethis slow a rate or slower, then a flow restrictor, such as a clamp orother valve structure may be provided on the tube 50 to decrease theflow rate.

The sand separator 42 preferably occupies space to effectively decreasethe cross-sectional area to about 25% (about 25 square inches) of thegreatest cross-sectional area of the sand in the system 10 (about 100square inches), which occurs at the top of the intermediate section 37.This decrease in cross-sectional area of the sand advantageously slowsdown the flow rate of water (flow per square inch) in the lower section38 where the sand remains predominantly clean and isolated from solidsin the water at higher locations in the sand, especially the uppermostlayer of sand that provides a bio layer, as previously described.

The described reduction in the area of the sand separator 42 that isoccupied by sand, that is the rapid reduction of the cross-sectionalarea occupied by sand from the top to the bottom, also offerssignificant reduction in the volume and weight of sand required. This isparticularly advantageous when the availability of suitable sand islimited in a geographic location in which the filter system is used.

It is desirable to slow the water flow through this region of the system10 to configure the system 10 to filter slower but require less frequentmaintenance, since as the upper portions of the sand become clogged withsolids, such clogging will not affect the filtration rate or otheroperation of the filter system until such time as the upper sand becomesabout 75% clogged, which is severely clogged. Thus, the filter system 10advantageously may be operated for long periods of time withoutmaintenance to clean the upper portion of the sand. In this regard, thesand separator 42 should decrease the cross-sectional area of the sandas described by at least about 50 percent, but most preferably fromabout 70 percent to about 80 percent.

The water treatment container 14 further includes a lid 60 to help keepdust and other contaminants out of the system 10 and the treated waterin the treated water container 12. As will be appreciated, the waterfiltration system 10 advantageously simplifies filtration of water bysimplifying the maintenance requirements. In addition, the constructionof the filter system that enables operation despite having substantialclogging of the sand reduces the maintenance frequency as compared toconventional filtration systems. Another significant advantage is thatby configuring the system for producing output water very slowly in thebackground on a continuing basis, the slow flow yields a far betterquality of output, up to ten times more pure than conventionalslow/intermittent but faster-flowing filters.

The foregoing description of preferred embodiments for this disclosurehas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the disclosure to the preciseform disclosed. Obvious modifications or variations are possible inlight of the above teachings. The embodiments are chosen and describedin an effort to provide the best illustrations of the principles of thedisclosure and its practical application, and to thereby enable one ofordinary skill in the art to utilize the disclosure in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the disclosure as determined by the appended claimswhen interpreted in accordance with the breadth to which they arefairly, legally, and equitably entitled.

What is claimed is:
 1. A water filtration system, comprising: a treatedwater container and a water treatment container located substantiallywithin the treated water container, the water treatment container beingconfigured to receive untreated water and to treat the untreated waterto yield treated water that is passed to the treated water container forstorage and/or dispensing; the treated water container comprising acontainer having a bottom and a sidewall extending upwardly from thebottom; the water treatment container comprising an upper sectionconfigured to receive a volume of water to be treated; a first and asand containing section within the container and below the upper sectionhaving sand that includes a bio-layer having a thickness at theuppermost portion of the sand; a sand separator comprising an invertedsolid-walled cone located within the sand containing section and in flowcommunication with the water treatment container, the exterior of theinverted cone of the sand separator being covered with sand andconfigured to separate sand in the water treatment container fromtreated water passing to the treated water container; and a flowpathextending upwardly into a bottom opening of the inverted cone of thesand separator via an opening in the bottom of the water treatmentcontainer to a location outside of the sand separator defining a treatedwater output, the treated water output being located at a height abovean upper surface of the sand in the sand containing section of the watertreatment container, wherein water flows through the sand and throughthe bottom opening of the inverted cone of the sand separator to enterthe flowpath.
 2. The system of claim 1, wherein the inverted cone of thesand separator decreases the cross-sectional area of the sand containingsection from an upper portion of the sand containing section to a lowersection of the sand containing section.
 3. The system of claim 1,wherein the water passes through the bio-layer at a flow rate of about0.10 meters per hour or less.
 4. The system of claim 1, wherein theinverted cone of the sand separator decreases the cross-sectional areaof the sand from an upper portion of the sand to a lower portion of thesand by an amount of at least about 50 percent.
 5. The system of claim1, further comprising a first removable debris filter within thecontainer and above the sand containing section.
 6. The system of claim5, further comprising a first filter retainer system to retain the firstdebris filter in place, the first filter retainer system comprising anannular groove defined on an interior sidewall of the water treatmentcontainer and a section of flexible tubing positioned within the annulargroove and having opposite abutting ends when installed in the groove,wherein the first debris filter is placed to adjacent the groove and theflexible tubing installed in the groove and the flexible tubing providesan outward force to retain the first debris filter in place.
 7. Thesystem of claim 5, further comprising a second removable debris filterspaced from the first debris filter and above the sand containingsection.
 8. The system of claim 1, wherein the flowpath comprises agenerally J-shaped tube located within the sand separator and having afirst open end located exterior of the water treatment container toprovide the treated water output.
 9. The system of claim 1, wherein thetreated water container, the water treatment container, the sandseparator, and the flowpath are of plastic construction.